Horseradish
Horseradish has been used medicinally and in kitchens for over 3,000 years. Often eaten with dishes that include beef or seafood, horseradish is a spicy and pungent zero calorie condiment. Label reading is important, because many brands contain cream or sugars which increase the caloric contents.

Lemon Juice (if you can stand it, I can't!)
Lemon juice, with its sweet and sour flavor combination, make it a zero-calorie condiment used in many kitchens and restaurants. Lemon juice is commonly added to dress up fish dishes and can freshen up a simple glass of water.

Salsa
Many salsas are low in cals, provide vitamin C and are also fat-free. Choose a low-sodium salsa that contains tomatoes and onions. If you like the taste of spicy foods, many salsas also contain jalapenos or other peppers. Make your own salsa by combining tomatoes, onions, peppers and garlic in a food processor and pureeing until smooth. Serve on cooked meats or with tacos or burritos.

Plain Yogurt
Salad dressing and mayonnaise are main ingredients in many recipes such as chicken salad or tossed salad. Replacing these high-fat and high calorie condiments with plain yogurt will help you stick to your diet and will add nutrition to your food as well. Plain yogurt is high in calcium and also contains protein, which will help satisfy your hunger for fewer fat and calories. Mix plain yogurt with skim milk and herbs for a healthy salad dressing or replace mayonnaise in recipes with plain yogurt for a similar taste and texture.

Ketchup
If you choose the right ketchup you will be able to enhance the taste of your food without adding too much salt or sugar to your meal. Many brands of ketchup contain added sugar and salt, which decreases how nutritious this condiment is. Look for natural ketchup because it is often made primarily of pureed tomatoes and spices and does not contain as much sugar and sodium as other brands. Ketchup complements the taste of many foods, including burgers, sandwiches, pasta dishes and eggs, so you can stick to your weight loss goals more easily.

Great one I tried recently:
Discovery Fajita Spices- very low in calories (like 9 per portion). Makes chicken un-boring, tastes great with anything salad, rice, or even how it's meant to be done in a wrap!